1. Field of the Invention
The present invention relates to a microcomputer and an evaluation device/method thereof.
2. Description of Related Art
A one-chip microcomputer is obtained as below. Specifically, a ROM (program memory), a RAM, a CPU and a peripheral circuit are integrated on a single semiconductor chip and this semiconductor chip is fixed on a substrate. Thereafter, an input/output port (peripheral circuit) formed on this semiconductor chip is connected to an external pin by wire bonding and the substrate having this semiconductor chip is covered with a resin member (insulating member) in a state where the external pin is exposed. Moreover, in some recent one-chip microcomputers, there is one in which, in consideration of time required for storing software in a ROM, manufacturing costs and the like, a nonvolatile memory (for example, an EEPROM) in which data can be electrically rewritten is integrated in place of a mask ROM.
In the meantime, data stored in the ROM of the one-chip microcomputer (for example, program data, table data and the like) are different according to an object to be controlled, which is controlled by the one-chip microcomputer. Thus, when the one-chip microcomputer has the above nonvolatile memory as the ROM, the data stored in the ROM are rewritten by use of data evaluated by a debugging tool (evaluation device) every time a type of the controlled body is changed.
Here, the debugging tool is a device which is connected to the one-chip microcomputer and reads in real time changes of address data in an address counter for specifying the addresses in the ROM, operation data based on program data in the ROM, and the like. Thus, the debugging tool evaluates validity of the program data. In such a manner, the data stored in the ROM can be rewritten and corrected.
Note that a technology related to the debugging tool is disclosed, for example, in Japanese Patent Application Laid-open Publication No. Hei11 (1999)-282713
However, a conventional debugging tool reads the address data in the address counter in real time and stores the entire data when the microcomputer is operated. Thus, a large-capacity volatile memory, nonvolatile memory or the like is required. Consequently, if a storage speed of the address data into the above-described memory is increased, a part of the address data may not be stored therein. Accordingly, there has been a problem that the data may not be evaluated correctly. Furthermore, there has also been a problem that the cost increases as the debugging tool grows in size.
Moreover, recently, in some of the one-chip microcomputers, an arithmetic processing speed thereof is increased to several hundred MHz. Thus, the conventional debugging tool cannot read changes of the address data, operation data and the like in real time. Consequently, there has been a problem that the data cannot be evaluated correctly.
Moreover, a package of the one-chip microcomputer, which is covered with the resin member, is miniaturized in consideration of a case where the package is built into small-sized equipments (for example, a digital camera and a portable telephone). Along with this miniaturization, a distance between the external pins is made extremely narrow. Thus, it is becoming physically impossible to read the address data, operation data, and the like by use of the conventional debugging tool. Consequently, similarly to the above case, there has been a problem that the data cannot be evaluated correctly.